Relationship between dental experiences, oral hygiene education and self-reported oral hygiene behaviour

Many preventive approaches in dentistry aim to improve oral health through behavioural instruction or intervention concerning oral health behaviour. However, it is still unknown which factors have the highest impact on oral health behaviours, such as toothbrushing or regular dental check-ups. Various external and internal individual factors such as education, experience with dentists or influence by parents could be relevant. Therefore, the present observational study investigated the influence of these factors on self-reported oral heath behaviour. One hundred and seventy participants completed standardized questionnaires about dental anxiety (Dental Anxiety Scale (DAS), and dental self-efficacy perceptions (dSEP)). They also answered newly composed questionnaires on oral hygiene behaviours and attitudes, current and childhood dental experiences as well as parental oral hygiene education and care. Four independent factors, namely attitude towards oral hygiene, attitude towards one’s teeth, sense of care and self-inspection of one’s teeth were extracted from these questionnaires by rotating factor analysis. The results of the questionnaires were correlated by means of linear regressions. Dental anxiety was related to current negative emotions when visiting a dentist and negative dental-related experiences during childhood. High DAS scores, infantile and current negative experiences showed significant negative correlations with the attitude towards oral hygiene and one’s teeth. Dental anxiety and current negative dental experiences reduced participants’ dental self-efficacy perceptions as well as the self-inspection of one’s teeth. While parental care positively influenced the attitude towards one’s teeth, dental self-efficacy perceptions significantly correlated with attitude towards oral hygiene, self-inspection of one’s teeth and parental care. Dental anxiety, dental experiences, parents’ care for their children’s oral hygiene and dental self-efficacy perceptions influence the attitude towards oral hygiene and one’s own oral cavity as well as the autonomous control of one’s own dental health. Therefore, oral hygiene instruction and the development of patient-centred preventive approaches should consider these factors.


OBJECTIVE(S)
The study objective is to assess the habitual toothbrushing performance and habits in students without relation to dentistry or psychology by means of video filming. Results from video assessment will be related to oral hygiene, several questionnaires on personality traits, body image and previous experiences with dentists and knowledge on oral hygiene. The primary purpose of this study is to explore current relationships and thereby to develop hypotheses for future research on oral health education

INCLUSION CRITERIA
Willing and able to give written informed consent Student at the University of Freiburg (at least 18 years of age) Not involved in dentistry (e.g. dental nurses or dental students) or in psychology (e.g. students in the field of psychology) Complete (including fixed dental restorations) and closed (except for extraction from orthodontic reasons) dental arches Sufficient German language skills Routine use of manual toothbrush EXCLUSION CRITERIA Fixed orthodontic appliances Removable dentures Mental or physical disability with the potential to influence oral hygiene Routine use of powered toothbrush

ENDPOINTS
First endpoint: correlation between TSI and sub-scores obtained from the questionnaires Other endpoints: Correlation between brushing performance (PI score) and the effective brushing duration, the frequency of alternations between brushing areas and TSI values Analysis of the influence of personal efforts regarding maintenance of oral health (e.g. frequency of visits at the dentist, the frequency of brushing per day) on the brushing performance (PI) und the brushing systematics (TSI) Correlation between the personal efforts regarding maintenance of oral health (e.g. frequency of visits at the dentist, the frequency of brushing per day) and the results of the DKB-35, the Neo-FFI and the PHQ-D.

TRIAL DESIGN
The study is a non-disguised, indirect, and structured observation study with healthy volunteers, no intervention other than the recording, classifying, counting and analysing of data takes place.

STATISTICAL ANALYSIS
For the primary endpoint analysis correlation coefficients for the pairwise correlations between the TSI-score and the single sub-scores obtained from the questionnaires will be computed.
The other endpoints will be analysed descriptively using regression models as appropriate for the respective type of data.  Caries prevention is an established field in dentistry, and due to the variety of public health preventative activities, the caries prevalence is declining in many countries. One main contributing factor is the wide use of topical fluorides via water fluoridation, products for daily home use, or professional applications. There is a tremendous body of literature on fluorides and meanwhile there is strong evidence about the preventive effects of different fluoridation strategies (1). Due to the practicability of fluoridation strategies and it's convincing effects, other fields of caries prevention, dietary counselling and proper tooth brushing, have been much less investigated. There is no doubt that toothbrushing is essential for removal of plaque and debris in order to contribute to good dental and periodontal health (2,3). Proper toothbrushing is of particular importance in preventing gingivitis and periodontitis, and for maintaining the outcome of periodontal treatments.

SAMPLE SIZE
Thus, oral hygiene strategies have reached scientific interest both in the field of periodontology and in the field of cariology.
The finding that providing oral hygiene advice has only variable success in influencing patient oral hygiene, however, has let to a certain extent of resignation. Most people find it difficult to clean their teeth sufficiently, and the daily experience in dental practice is that patients exhibit plaque even though they reportedly engage in oral hygiene. As a result, oral hygiene instruction is content of preventive programmes, but an under-researched area. Most publications on the topic are from the field of periodontology, but in all there is only little evidence on what brushing technique is most effective or how to influence patient behaviour (4). For interpreting results from oral hygiene studies, two basic points need to be considered. The first is the theoretical efficacy of tooth cleaning strategies, and it is obvious that the absence of plaque is related to the absence of plaque induced diseases i.e. gingivitis/periodontitis and caries. The second point is the practical efficacy of tooth cleaning strategies, the measure of which in the majority of studies is reduction of plaque levels. The latter, however, is a surrogate parameter as to research questions on oral hygiene techniques and its performance. Lack of reduction of plaque levels does not say anything about the practical efficacy of oral hygiene techniques, as long as nothing is known about the practical performance of oral hygiene, and the skills and dexterity of the included volunteers.
Interestingly, only few studies address these shortcomings of using plaque levels as a surrogate for brushing habits and investigate the brushing performance of volunteers by observing them during practicing the hygiene technique (5-10). These studies, however, have clearly shown that persons, being video-taped during their habitual toothbrushing, mostly brush more or less non-systematically and often do not reach all areas. Often the oral part of the mandible teeth is not brushed (10,11). In addition volunteers alter frequently between predefined areas, probably reducing the brushing efficacy in the respective area. A further very interesting outcome of these studies was that the inter-personally brushing habits show a wide variation; however, intra-personally the brushing habits are very constant or stable (12)(13)(14). The latter speaks for a deep rootedness of the movement patterns (15,16).
There are indications that a psychological intervention in combination with oral hygiene instructions can lead to an increase of brushing efficacy; however, the evidence is low (17). Furthermore, nothing is known about the relationship between personality traits (e.g. conscientiousness or neuroticism), body image (e.g. acceptance of one's body) and brushing performance as well as brushing efficacy. It is quite conceivable that differences in personality traits or experience with dentist as well as dental fear influence the brushing habits. The aim of the present study is therefore to film a group of volunteers (students without relation to any topic of the study -dentistry or psychology) during their habitual oral hygiene and to evaluate the personality traits and body image as well as experience with dentistry by means of different questionnaires.

STUDY OBJECTIVE
The study objective is to assess the habitual toothbrushing performance and habits in students without relation to dentistry or psychology by means of video filming. Results from video assessment will be related to oral hygiene, several questionnaires on personality traits, body image and previous experiences with dentists and knowledge on oral hygiene. The primary purpose of this study is to explore current relationships and thereby to develop hypotheses for future research on oral health education.

INVESTIGATIONAL PLAN 6.1 OVERALL STUDY DESIGN AND PLAN
The study is a non-disguised, indirect, and structured observation study with healthy volunteers, no intervention other than the recording, classifying, counting and analysing of data takes place.

DISCUSSION OF THE STUDY DESIGN
Volunteers in disguised observations tend to act more naturally and the data collected tends to reflect their true reactions. The primary concern with disguised observation however is the ethical concern over recording behavioural information that would normally be private or not voluntarily revealed to a researcher. Therefore, a non-disguised observation design was chosen. To overcome at least partly the disadvantages of a nondisguised observation, the filming was performed through a mirror so that the volunteers should feel less observed than with an obviously visible camera. Contrary to expectations, however, filming appears to have limited influence on brushing performance. A study comparing video films from volunteers unaware or aware of being filmed revealed that there was no difference in brushing time and influenced performance only to a small extent (16). The assumption that the awareness of being filmed has little effects is also supported by the finding that in repeated video recordings the brushing performance of a volunteer showed a remarkable reproducibility (17). Mierau et al. (18) arrived at similar conclusions when assessing brushing habit patterns in the course of nine sessions; variations in force, duration, and technique as well as in the sequence of brushing positions and number of changes of brushing sites were small. Besides limitations due to the observational setting, it must be emphasised that the study population is limited in number and is not representative. Observed results need to be interpreted within these limitations.

6.4
STUDY POPULATION Volunteers to be included are male and female volunteers living in Freiburg and studying at the University in Freiburg with no relation to dentistry and psychology. They will be recruited via advertisements at noticeboards at central points of the University. Group size is 170. The video films will be analysed under blind conditions as to the questionnaires. This is achieved by retaining the respective parts of the CRF´s until termination of the video assessments. The questionnaires will be analysed under blind conditions as to the video films.

FLOW CHART
Study protocol final version and Ethics Commission after approval, recruitment of volunteers, volunteers receive appointment, at this appointment: inclusion/exclusion criteria, informed consent, inclusion of the volunteer plaque index supply of toothbrush video recording supply of questionnaires payment of allowance after termination of the observation phase: assessment of video recordings after termination of the assessment of video recordings: transfer from source data to database (questionnaires and raw data of video recording) statistical procedures

STUDY PARAMETERS Parameters under study are:
Clinical parameters Plaque Index (PI) (18). The scores are: 0 -no plaque, 1 -plaque invisible but can be found with periodontal probe at the gingival margin, 2 -moderate plaque easily seen without probing, 3 -ample plaque easily seen. The PI is scored on two surfaces (that is buccal, oral) of all teeth without disclosing. An overall PI score is computed as suggested (18). Additionally, the maximum value per sextant is recorded and the percentage of surfaces showing a PI above 0.

Parameter Description Handedness
Hand holding the toothbrush (left, right or both).
Total brushing duration Time between the first contact of the toothbrush with teeth, and the last action of brushing. Effective brushing duration Total brushing duration without interruptions like rinsing, spitting or breaks.

Starting location
The first approached area (oral, vestibular, occlusal, and right side, left side or anterior) at the beginning of toothbrushing.

Brushing events
Frequency of alternations between the sextants, the tooth surfaces (oral, vestibular and occlusal) or a combination of both. TSI (Toothbrushing Systematics Index)

Analysis and calculation on the basis of the assessed brushing parameters
Questionnaires -Socio-demographic data (according to Deutsche Mundgesundheitsstudie V (19)) -Toothbrushing education and toothbrushing habits (self-estimation, according to Deutsche Mundgesundheitsstudie V (19)) -Relation to oral hygiene and the own oral cavity -Experience with dentists -Dental related self-efficacy (20,21) -General self-efficacy expectation (Allgemeine Selbstwirksamkeitserwartung (SWE), German version (22)

PROCEDURES
Volunteers are screened as to the inclusion/exclusion criteria and informed consent is obtained. At the same appointment, the PI is determined, afterwards the volunteers are asked to brush their teeth in their usual way standing/sitting in front of a mirror. Each volunteer is provided with a standard toothbrush. Brushing is performed without toothpaste to facilitate the assessment of the video recordings. While brushing, each volunteer is filmed through the mirror without the investigator present. The video film is saved on the computer with the volunteer's code as file name. After filming the questionnaires are delivered. After completion of the procedure the allowance is paid.
The video films are analyzed after termination of the observation phase. The data is directly transferred to an excel file, which represent the source data. The brushing duration is determined from the video display; the other parameters are obtained from visual judgment of the volunteer's behavior. The answers on the questionnaires are transferred to electronic files.

QUALITY CONTROL AND DATA MANGEMENT 10.1 GOOD CLINICAL PRACTICE
The study will be conducted along the European directives and ICH Harmonised Tripartite Guideline for good clinical practice E6 (R1 as from June 2017 R2): Note for Guidance on Good Clinical Practice, CPMP/ICH/135/95 Step5.

CALIBRATION AND TRAINING OF INVESTIGATORS
The Principal Investigators will perform sufficient calibration and training procedures. Prof. Schlueter will calibrate the clinical investigators as to assessment of PI and to the analysis of the video recordings. Prof. Zeeck will supervise the investigator's analysis of the questionnaires. The Department f. Zahn-, Mund-u. Kieferheilkunde, Klinik f. Zahnerhaltungskunde und Parodontologie will provide sufficient opportunities for practising all procedures and will assure good performance.

CASE REPORT FORMS (CRF)
All of the information collected during the study (PI, questionnaires) will be recorded in the CRF´s identified by the volunteer number. The data obtained from video analysis will be directly transferred to electronic files without noting them in the CRF. An example of the CRF is added in the appendix. The Investigators will ensure that the CRFs are properly and completely filled in. Each page must be signed or initialled by the Investigators, signifying agreement with and responsibility for the recorded data. The Investigators have to identify all data that were directly recorded into the CRF (i.e. no prior written or electronic record of data), and to be considered to be source data. The CRFs will be checked for completeness and plausibility by the Principal Investigators. The Investigators will resolve any queries.

AUDITS AND INSPECTIONS
The Principle investigators will audit all clinical and assessment procedures in their responsibility on a regular basis. The Investigators and Principle Investigators will make themselves available for each other and will give access to the technical site, the study material, and to volunteer files. The volunteers' anonymity must be safeguarded and data checked during the audit remain confidential.

DATA MANAGEMENT
All data collected in the CRFs of this study will be entered into a computer database after termination of the video assessments and will be checked for plausibility. Any discrepancies or errors will be clarified and corrected.

STATISTICAL METHODS AND DETERMINATION OF SAMPLE SIZE 11.1 STATISTICAL ANALYSIS PLAN
Definition of outcome measures and study objectives Purpose of the study is to describe quality of current brushing behaviour in adults and thereby to identify needs for further dental education and to associate this with the outcome of the questionnaires to identify predictors for brushing habits.
In a first step the study population will be described with respect to socio-demographic and behavioural characteristics (brushing behaviour). The behavioural characteristics are the following: -duration of tooth brushing (sec) -starting location -type of strokes per sextant -number of movements between areas -Toothbrushing systematics From these data the TSI will be calculated.
In parallel, the information obtained from the questionnaires will be stored in MS-Access-Databases. The scoring of the questionnaires relies on MS-Access-Basic scripts which are already available at the Department of Psychosomatic Medicine and Psychotherapy. The scripts for DKB-35, NEO-FFI and PHQ-D were programmed according to published manuals or articles. These scripts were double checked and debugged. An equivalent procedure will be run for the Dental Anxiety Scale and the Dental Related Self-efficacy. All other forms (e.g. sociodemographic data) do not require standardized scoring procedures. All scores and descriptive data will be exported into a data table, which is compatible with common statistical analysis software (preferably MS-Excel, *.xlsx).
The primary study aim is to correlate the individual brushing habits (effective brushing duration, frequency of alternations between brushing areas, TSI values) with the single scores and sub-scores obtained from the questionnaires.
Secondary objective is to correlate the brushing performance (PI score) with the effective brushing duration, the frequency of alternations between brushing areas and TSI values.
Furthermore the influence of personal efforts regarding maintenance of oral health (e.g. frequency of visits at the dentist, the frequency of brushing per day) on brushing performance (PI) and brushing systematics (TSI) will be analysed.
The third objective is to correlate the personal efforts regarding maintenance of oral health (e.g. frequency of visits at the dentist, the frequency of brushing per day) with the results of the DKB-35, the Neo-FFI and the PHQ-D.

Statistical Analysis
For the primary endpoint analysis correlation coefficients for the pairwise correlations between the TSI-score and the single sub-scores obtained from the questionnaires will be computed. The other endpoints will be analysed descriptively using regression models as appropriate for the respective type of data.

SAMPLE SIZE CALCULATION
Calculation of sample size are based on own data from a previous study (5) including a comparable population (students without relation to dentistry). From these data a toothbrushing systematics index was developed (TSI, unpublished results). It is intended to use the index as a measure for differences and changes in systematics of participants. A maximum TSI score of 2 can be reached. Non-instructed participants have a mean index score of 1.2 with a MIN of 0.6, a MAX of 1.6 and a SD of 0.3. A difference in TSI score between systematically and non-systematically habitual toothbrushing of 0.15 can be assumed to be clinically relevant. With α = 0.05 and β = 0.1 a sample size of 170 can be calculated.

12
PROTOCOL AMENDMENTS Changes or deviations in the conduct of this protocol will be only permitted after discussion with all persons with responsibilities in the study. The Ethics Commission which granted approval for the study must be notified of all changes in the protocol and must provide written approval if changes are substantial (e.g. change of/within study population, number of participants). In the case that an amendment is made, Prof. Schlueter or Prof. Zeeck will be responsible for notification of the Ethics Commission.

RELEVANT AUTHORITIES
This study is to be conducted in accordance with the ethical principles of the Declaration of Helsinki and according to the principle of Good Clinical Practice. Before starting the study, the study protocol will be subject of review by the IEC. No volunteer should be admitted to the study before the IEC issues its written approval opinion of the study.

VOLUNTEER INFORMATION AND INFORMED CONSENT
To all volunteers, the Investigator will explain the kind of trial and the risks involved, and the informed consent will be obtained from and signed by each individual volunteer before screening and inclusion of each individual volunteer. The volunteer will also be informed that she/he is free to withdraw from the trial at any time. Examples of the volunteer information sheet and the informed consent form are given in the appendix.

VOLUNTEER INSURANCE AND ALLOWANCE
As no invasive intervention is planned no insurance against injury caused by the procedures related to the study is necessary. The allowance will be 15 Euro per volunteer.

VOLUNTEER DATA PROTECTION AND RETENTION OF STUDY RECORDS
The study will be performed without recording the volunteer's names, addresses or telephone numbers. All files will be coded by an ID number generated by a random number generator. Other personal data as to social status, age, or gender will be kept under the strict confidence by the Investigator. The files pertaining to this study will be kept for a period of 10 years from the day of delivery of the final report to the IEC. A Principal Investigator (Prof. Schlueter) will retain originals of the approved study protocol, copies of completed CRFs, volunteers' participation agreements, relevant source documents and all other supporting documentation related to the study for a period of 10 years. The videos will be backed up on a suitable storage medium. All files must be made available for inspection of all Principal Investigators.

PUBLICATION / PRESENTATION
The study results will be published, preferably in an indexed journal. Any publication will name either a member of the Department f. Zahn-, Mund-u. Kieferheilkunde, Klinik f. Zahnerhaltungskunde und Parodontologie as first and a member of the Klinik f. Psychosomatische Medizin u. Psychotherapie as last author or vice versa.